Soil testing your garden in the fall is a good way to prepare for next spring’s growing season. I recently took a soil sample from both of our gardens. I filled two large butter containers with soil that I had dug from the center of each garden and from 4-6 inches. We took them to our local university extension office and completed a short form which asked what kinds of tests we wanted on the samples. I requested the basic soil test which determines the adequacy of nitrogen, potassium (potash), and phosphorus levels and the pH.
We received the results about ten days later. We already knew that our soil was mostly clay, but we learned our soil also has an excessive amount of phosphorus and needs more calcium. To increase the calcium the extension office recommended that we add 46 lbs per 1000 sq. ft. of gypsum for one garden and 114 lbs per 1000 sq. ft. in the other. Gypsum can be added any time of the year, so we’ll add ours in the spring. They also recommended that we minimize the use of balanced blend fertilizers such as 10-10-10 because the soil doesn’t want or need more phosphorous and potash. In fact, adding more phosphorous would burn plant roots.
I’m so glad we had the soil tested. Now that I’m armed info, I hope to give our garden what it needs rather than blindly throwing expensive fertilizers at it. I’m eager to see what kind of results we’ll get next year after the gypsum application.